Horizontal line data position and burst phase encoding apparatus and method

Abstract

Information related to the beginning of data and the phase of color burst on consecutive horizontal scan lines of a digital color television signal is encoded into a variable width pulse. A first transition of that pulse has a predetermined phase relationship with the beginning of data on each line. A second transition of the variable width pulse is formed by providing a delayed transition with respect to the first transition in a variable delay circuit. The second transition is delayed by different amounts of delay, each corresponding to a particular predetermined color burst phase on that particular line.

What is claimed is: 
     
       1. In a system for processing a digitally encoded composite color television signal comprising a horizontal line synchronizing signal and a color burst signal having predetermined phase relationships to said horizontal line synchronizing signal which differ on consecutive horizontal lines of said color television signal, apparatus for encoding information related to a beginning of data pertaining to each horizontal line and to a phase of said color burst signal on consecutive lines of said digitally encoded signal, said apparatus comprising: variable width pulse forming means, coupled to receive a first synchronizing signal having a predetermined phase relationship with said horizontal line synchronizing signal and a frequency corresponding thereto, for providing a variable width output pulse having a first transition of a predetermined phase relationship with said first signal;   delay control means, coupled to receive a signal indicating said predetermined phase relationship of said color burst signal at a beginning of each horizontal line, for providing respective delay control signals for respective values of said phase relationship; and   variable delay means coupled to receive said delay control signals, for applying responsively a delayed control signal to a control input of said variable width pulse forming means, said variable width pulse forming means coupled to provide a second transition of said variable width output pulse in response to said delayed control signal.   
     
     
       2. The system of claim 1 wherein said delayed control signal is provided by delaying said first transition by a different amount of delay in response to each said respective delay control signal. 
     
     
       3. In a system for processing a digitally encoded composite color television signal comprising a horizontal line synchronizing signal and a color burst signal having predetermined phase relationships to said horizontal line synchronizing signal which differ on consecutive horizontal lines of said color television signal, apparatus for encoding information related to a beginning of data pertaining to each horizontal line and to a phase of said color burst signal on consecutive lines of said digitally encoded signal, said apparatus comprising: variable width pulse forming means coupled to receive a first synchronizing signal having a predetermined phase relationship with said horizontal line synchronizing signal and a frequency corresponding thereto, for providing a variable width output pulse having a first transition of a predetermined phase relationship with said first signal;   delay control means, coupled to receive a signal indicating said predetermined phase relationship of said color burst signal at a beginning of each horizontal line, for providing respective delay control signals for respective values of said phase relationship; and   variable delay means, coupled to receive said first transition of said variable width output pulse provided by said pulse forming means, for delaying said first transition by a different amount of delay in response to each said respective delay control signal and applying said delayed first transition to a control input of said pulse forming means to obtain a second transition of said variable width output pulse provided thereby.   
     
     
       4. The system of claim 3 wherein said variable delay means comprises at least two series delay means, each for delaying said first transition by a predetermined number of clock cycles. 
     
     
       5. The system of claim 4 wherein said variable delay means further comprises gate means, said gate means having respective first inputs, each coupled to receive one said delay control signal provided by said delay control means and respective second inputs, each coupled to an output of one said series delay means, for providing respective output signals each delayed by a different number of clock cycles in response to each said delay control signal. 
     
     
       6. The system of claim 3 wherein said apparatus is coupled to receive a clock signal having a frequency equal to an even multiple number of a frequency of said color burst signal. 
     
     
       7. The system of claim 3 wherein said respective delay control signals are provided by said delay control means in a sequence corresponding to that of said predetermined different phase relationships of said color burst signal on consecutive horizontal lines. 
     
     
       8. The system of claim 3 wherein said signal indicating said predetermined phase relationship of said color burst signal is a second synchronizing signal having a predetermined phase relationship with said first synchronizing signal and having one-half of the frequency of said horizontal line synchronizing signal. 
     
     
       9. The system of claim 8 wherein said first synchronizing signal applied to said variable width pulse forming means is delayed with respect to said second synchronizing signal. 
     
     
       10. The system of claim 3 wherein said signal indicating said predetermined phase relationship of said color burst signal comprises a second and a third synchronizing signal, each signal having a predetermined phase relationship with said first synchronizing signal, said second signal having one-half of the frequency and said third signal having one-quarter of the frequency of said horizontal line synchronizing signal. 
     
     
       11. The system of claim 10 wherein said first synchronizing signal applied to said variable width pulse forming means is delayed with respect to both said second and third synchronizing signals. 
     
     
       12. The system of claim 3 wherein said variable pulse width forming means comprises an input flip-flop having a D-input coupled to a predetermined logic level, a clock input coupled to receive said first synchronizing signal and a reset input coupled to an output of said variable delay means. 
     
     
       13. The system of claim 8 wherein said delay control means comprises a control flip-flop having an input coupled to receive said second synchronizing signal, a clock input coupled to receive a clock signal having an even multiple frequency of said color burst signal and having a first output providing a non-inverted first delay control signal and a second output providing an inverted second delay control signal. 
     
     
       14. The system of claim 10 wherein said delay control means comprises a decoding means having a first and a second input, each coupled to receive one of said second and third synchronizing signals, said decoding means coupled to provide four different output signals, each corresponding to a distinct combination of logic signal levels of said input signals at the occurrence of a selected edge of said first synchronizing signal. 
     
     
       15. In a system for processing a digitally encoded composite color television signal, comprising a horizontal line synchronizing signal and a color burst signal having predetermined phase relationships to said horizontal line synchronizing signal which differ on consecutive horizontal lines of said color television signal, apparatus for encoding information related to a beginning of data pertaining to each horizontal line and to a phase of said color burst signal on consecutive lines of said digitally encoded signal, said apparatus comprising: variable width pulse forming means coupled to receive a first synchronizing signal having a predetermined phase relationship with said horizontal line synchronizing signal and a frequency corresponding thereto, for providing a variable width output pulse having a first transition of a predetermined phase relationship with said first signal;   delay control means, coupled to receive a signal indicating said predetermined phase relationship of said color burst signal at a beginning of each horizontal line, for providing respective delay control signals for respective values of said phase relationship; and   variable delay means, coupled to receive said first transition of said variable width output pulse provided by said pulse forming means, said variable delay means comprises at least two series delay means, each for delaying said first transition by a different amount of delay in response to each said respective delay control signal, and gate means having respective first inputs, each coupled to receive one said delay control signal provided by said delay control means and respective second inputs, each coupled to an output of one said series delay means, for providing respective output signals each delayed by a different amount of delay in response to each said delay control signal and for applying said delayed output signals to a control input of said pulse forming means to obtain a second transition of said variable width output pulse provided thereby.   
     
     
       16. The system of claim 15 wherein said variable width pulse forming means comprises an input flip-flop having a D input coupled to a predetermined logic level, a clock input coupled to receive said first synchronizing signal and a reset input coupled to an output of said variable delay means, and wherein said delay control means comprises a control flip-flop having an input coupled to receive said second synchronizing signal, a clock input coupled to receive a clock signal having an even multiple frequency of said color burst signal and having a first output providing a non-inverted first delay control signal and a second output providing an inverted second delay control signal. 
     
     
       17. In a system for processing a digitally encoded composite NTSC color television signal comprising a horizontal line synchronizing signal and a color burst signal having a zero degree and a 180 degree phase relationship to said horizontal line synchronizing signal at the beginning of consecutive horizontal lines of said color television signal, apparatus for encoding information related to a beginning of data pertaining to each horizontal line and to said phase of said color burst signal on consecutive lines of said digitally encoded signal, said apparatus comprising: variable width pulse forming means, coupled to receive a first synchronizing signal having a predetermined phase relationship with and a frequency corresponding to said horizontal line synchronizing signal, for providing a variable width output pulse having a first transition of a predetermined phase relationship with said first synchronizing signal;   delay control means, coupled to receive a second synchronizing signal having a first logic value indicating said zero degree phase, and a second logic value indicating said 180 degree phase, at the beginning of said consecutive horizontal lines, for providing a first and a second delay control signal, respectively, in response to each said value of said second synchronizing signal; and   variable delay means coupled to receive said first transition of said variable width output pulse provided by said pulse forming means, said variable delay means comprises two series delay means, each for delaying said first transition by a different amount of delay in response to each said respective delay control signal, and gate means having respective first inputs, each coupled to receive one said delay control signal provided by said delay control means and respective second inputs, each coupled to an output of one said series delay means, for providing respective output signals each delayed by a different amount of delay in response to each said delay control signal and applying said delayed output signals to a control input of said pulse forming means to obtain a second transition of said variable width output pulse provided thereby.   
     
     
       18. In a system for processing a digitally encoded composite PAL color television signal comprising a horizontal line synchronizing signal and a color burst signal having predetermined phase relationships to said horizontal line synchronizing signal which differ on consecutive horizontal lines within each group of four consecutive lines of said color television signal, apparatus for encoding information related to a beginning of data pertaining to each horizontal line and to a phase of said color burst signal on consecutive lines of said digitally encoded signal, said apparatus comprising: variable width pulse forming means, coupled to receive a first synchronizing signal having a predetermined phase relationship with said horizontal line synchronizing signal and a frequency corresponding thereto, for providing a variable width output pulse having a first transition of a predetermined phase relationship with said first synchronizing signal;   delay control means comprising a decoding means, coupled to receive a second and a third synchronizing signal, said second synchronizing signal having one-half of the frequency and said third synchronizing signal having one-quarter of the frequency of said horizontal line synchronizing signal, said decoding means for providing four different delay control signals, each corresponding to a distinct combination of logic signal levels of said input signals at the occurrence of a selected edge of said first synchronization signal; and   variable delay means coupled to receive said first transition of said variable width output pulse provided by said pulse forming means, said variable delay means comprises four series delay means, each for delaying said first transition by a different amount of delay in response to each said respective delay control signal and gate means having respective first inputs, each coupled to receive one said delay control signal and respective second inputs, each coupled to an output of one said series delay means, for providing respective output signals each delayed by a different amount of delay in response to each said delay control signal and to apply said delayed output signals to a control input of said pulse forming means to obtain a second transition of said variable width output pulse provided thereby.   
     
     
       19. A method of encoding information related to a beginning of data pertaining to each horizontal line and to a phase of a color burst signal of a digitally encoded composite color television signal, said composite signal comprising a horizontal line synchronizing signal and a color burst signal having a known predetermined phase relationship to said horizontal line synchronizing signal on consecutive horizontal lines of said color television signal, comprising the steps of: providing a variable width pulse having a first transition having a predetermined phase relationship with said horizontal line synchronizing signal;   providing respective delay control signals, each corresponding to one said known predetermined phase relationship of said color burst signal at a beginning of each consecutive horizontal line; and   delaying said first transition by a predetermined different amount of delay in response to each respective delay control signal, to obtain a second transition of said variable width pulse.